Diagnostic precision of coronary angiotomography of 64 slices in the assessment of symptomatic patients after going to myocardial revascularization, a comparative study with conventional coronary angiograpy

Abstract

Conventional coronary angiograpy is still considered the standard method for assessment of obstructions in aorto coronarious grafts, as well as for native coronary arteries. Nevertheless new generations of multislice computed tomography (MCT) have shown accuracy for identification of permeability of coronarial bypasses as well as for the assessment of native coronary arteries which receive distal anastomoses. Objectives: our aim was to assess operative properties of MCT obtained from 64 slices of symptomatic patients who were taken to myocardial revascularization. Methodology and results: coronary angiography by MCT of 64 detectors was performed in 92 symptomatic patients, 9.3±7.8 years after myocardic revascularization. 56 patients (61%) had gone to at least one ischemic inductor test at the beginning of symptoms. 92% of patients were also taken to conventional coronary angiography within days 16.9±9,1 after MCT. Only segments which presented angiographic confirmation were analyzed by two independent observers, resulting in an analysis of 201 coronary bypasses (77 arterial bypasses and 124 venous bypasses), with a total of 603 analyzed segments (231 arterial, 372 venous). Also 200 segments correspondent to distal runoff segments and 140 native coronaries were analyzed. Sensitivity, specificity, predictive positive value and negative predictive value of coronary angiography by MCT for the detection of significant obstructions (stenoses or total occlusions) for all bypasses was of 98%, 98.6%, 96.5% y 99.3%, respectively. In relationship to segments (proximal, medial and distal) of each bypass (arterial and venous) a sensitivity of 98.6% was reported with an specificity of 99%. The presence of obstructive lesions was significantly higher in revascularizated distal segments than in coronary bypasses (39%[78/200] vs. 28%[56/201]; p=0,026). In relation to native coronary arteries, a total of 140 were assessed (420 coronary segments) resulting in a predictive positive value of 67% and a specificity of 86%. This in relation to the over estimation of severity of lesions, which was shown by the presence of 15 false positive and one false negative. Conclusions: results shown by our study suggest that obstructive disease of coronary bypasses can be detected with a high diagnostic accuracy by using coronary angiograpy of 64 slices in a selected population.